In general, an integrated circuit generates and uses an internal control signal so as to perform various internal operations. The internal control signal generated in the integrated circuit is regulated as to the current amount, the voltage level, the frequency and so forth thereof to control the internal operations.
While the current amount, the voltage level, the frequency and so forth of the internal control signal are regulated during the internal operations of the integrated circuit, they are also regulated through a test performed during a wafer process. For example, by performing a test capable of setting the frequency of an internal control signal to a target value during a wafer process, the refresh cycle of a semiconductor memory device which is mounted to an integrated circuit may be regulated.
In order to regulate the current amount, the voltage level, the frequency and so forth of an internal control signal, in a test mode which is established during a wafer process, a fuse programming scheme is mainly adopted such that a refresh cycle is measured and the connection states of fuses included in an integrated circuit are regulated. Fuse programming is performed in a physical way of changing the connection states of fuses from short states to open states using a laser beam.
Even though a test for regulating an internal control signal is performed during a wafer process, variations may occur in the current amount, the voltage level, the frequency and so forth of the internal control signal while annealing is performed during a packaging process. Accordingly, it is necessary to perform a test for regulating an internal control signal in the packaging process. However, lots of time and cost are required to measure and regulate the current amount, the voltage level, the frequency and so forth of the internal control signal which has undergone a variation, in every package.